Answer: The sentence 'There is some dissension about whether we need to learn a 2nd language, or we don't need to learn a second language' is a compound sentence.
Step-by-step explanation:
Compound sentences are the ones which contains at least two independent clauses. They make a sentence of their own without any dependent clause.
The sentence’ There is some dissension about whether we need to learn a 2nd language, or we don't need to learn a second language’ is a compound sentence because it consists of two independent clauses. This sentence consists of two different sentences i.e. ‘There is some dissension about whether we need to learn a 2nd language’ and ‘We don’t need to learn a second language.’ which don’t need any dependent clause.